1. Field of the Invention
The present invention relates to horizontal swiveling angle positioning means for a chair, and more particularly, the horizontal swivelling angle positioning means for a motor driven wheelchair for disabled people.
2. Brief Description of the Prior Art
A motor driven wheelchair for disabled people or a common round chair or an armchair for the office or the family use often needs to be able to adjust its horizontal swivelling angle. However, a conventional swivel chair usually has no means to be positioned in the direction after it has been turned thereat. As for a conventional motor driven wheelchair, the horizontal swiveling positioning is simply carried out by a set screw tightened between an axle seat (or axle bush) and an axle. Positioning procedure is performed by at first slackening the set screw; swivelling the horizontal angle of the wheelchair to a predetermined direction; and then tightening the set screw. However, there are disadvantages that a tool, for example, at least a driver is required for the work that is particularly embarrassing to an aged person or a disabled one (perhaps he/she is unable to do). Besides, the rider must stand up from the wheelchair during a third person is working for him/her. In the case the swivelling angle is to be recovered to the original position, the above mentioned tedious work has to be repeated.
Besides, the work has to be done in a quite narrow working space, and the set screw is not so reliable because it is easy for it to become loose gradually caused by continuous vibration of the moving wheelchair.
In order to solve the above described problems, the applicant has carried out theoretical studies and practical experients for a long time for the present invention.